A person is under this Act to have the right of abode in the United Kingdom if—
he is a British citizen; or
he is a Commonwealth citizen who—
immediately before the commencement of the British Nationality Act 1981 was a Commonwealth citizen having the right of abode in the United Kingdom by virtue of section 2(1)(d) or section 2(2) of this Act as then in force; and
has not ceased to be a Commonwealth citizen in the meanwhile.
In relation to Commonwealth citizens who have the right of abode in the United Kingdom by virtue of subsection (1)(b) above, this Act, except this section , section 5(2) and section 25, shall apply as if they were British citizens; and in this Act (except as aforesaid) "British citizen" shall be construed accordingly.